Caries Model Research Articles

Protein relative abundance patterns associated with sucrose-induced dysbiosis are conserved across taxonomically diverse oral microcosm biofilm models of dental caries.

BackgroundThe etiology of dental caries is multifactorial, but frequent consumption of free sugars, notably sucrose, appears to be a major factor driving the supragingival microbiota in the direction of dysbiosis. Recent 16S rRNA-based studies indicated that caries-associated communities were less diverse than healthy supragingival plaque but still displayed considerable taxonomic diversity between individuals. Metagenomic studies likewise have found that healthy oral sites from different people were broadly similar with respect to gene function, even though there was an extensive individual variation in their taxonomic profiles. That pattern may also extend to dysbiotic communities. In that case, shifts in community-wide protein relative abundance might provide better biomarkers of dysbiosis that can be achieved through taxonomy alone.ResultsIn this study, we used a paired oral microcosm biofilm model of dental caries to investigate differences in community composition and protein relative abundance in the presence and absence of sucrose. This approach provided large quantities of protein, which facilitated deep metaproteomic analysis. Community composition was evaluated using 16S rRNA sequencing and metaproteomic approaches. Although taxonomic diversity was reduced by sucrose pulsing, considerable inter-subject variation in community composition remained. By contrast, functional analysis using the SEED ontology found that sucrose induced changes in protein relative abundance patterns for pathways involving glycolysis, lactate production, aciduricity, and ammonia/glutamate metabolism that were conserved across taxonomically diverse dysbiotic oral microcosm biofilm communities.ConclusionsOur findings support the concept of using function-based changes in protein relative abundance as indicators of dysbiosis. Our microcosm model cannot replicate all aspects of the oral environment, but the deep level of metaproteomic analysis it allows makes it suitable for discovering which proteins are most consistently abundant during dysbiosis. It then may be possible to define biomarkers that could be used to detect at-risk tooth surfaces before the development of overt carious lesions.Electronic supplementary materialThe online version of this article (doi:10.1186/s40168-015-0136-z) contains supplementary material, which is available to authorized users.

Efficacy of amelogenin-chitosan hydrogel in biomimetic repair of human enamel in pH-cycling systems.

Amelogenin-chitosan (CS-AMEL) hydrogel has shown great potential for the prevention, restoration, and treatment of defective enamel. As a step prior to clinical trials, this study aimed to examine the efficacy of CS-AMEL hydrogel in biomimetic repair of human enamel with erosive or caries-like lesions in pH-cycling systems. Two models for enamel defects, erosion and early caries, were addressed in this study. Two pH-cycling systems were designed to simulate the daily cariogenic challenge as well as the nocturnal pH conditions in the oral cavity. After pH cycling and treatment with CS-AMEL hydrogel, a synthetic layer composed of oriented apatite crystals was formed on the eroded enamel surface. CS-AMEL repaired the artificial incipient caries by re-growing oriented crystals and reducing the depth of the lesions by up to 70% in the pH-cycling systems. The results clearly demonstrate that the CS-AMEL hydrogel is effective at the restoration of erosive and carious lesions under pH-cycling conditions.

Effect of the Probiotic Lactobacillus rhamnosus LB21 on the Cariogenicity of Streptococcus mutans UA159 in a Dual-Species Biofilm Model

Despite promising results using probiotics, evidence of the preventive effect on enamel demineralization is insufficient and the cariogenic potential of probiotics is still controversial. Probiotics could affect biofilm formation and interfere with adherence, growth or coaggregation with Streptococcus mutans in biofilms. However, most of the studies have been conducted using planktonic bacteria. Hence, the aim of the study was to assess the effect of probiotic bacteria on the cariogenicity of S. mutans using an in vitro biofilm caries model on enamel. Single-species biofilms (S. mutans UA159, SM or Lactobacillus rhamnosus LB21, LB) or dual-species biofilms simultaneously inoculated (SM + LB) or LB inoculated 8 h after SM (SM → LB) were grown for 96 h. Biofilms were formed on bovine enamel saliva-coated slabs of known surface hardness (SH) and immersed in culture media. Biofilms were exposed 8 times per day to 10% sucrose. Medium pH was monitored twice daily as a biofilm acidogenicity indicator. After 96 h, biofilms were collected to determine biomass and bacteria viability. Slab demineralization was calculated as percentage of SH loss (%SHL). Additionally, the model was tested with different concentrations of the initial inoculum (10³, 10⁶, 10⁸ cells/ml) and different adhesion times (2 or 8 h). The dual-species biofilm revealed no LB effects on SM cariogenicity, without changes in acidogenicity or %SHL among groups (p > 0.05, n = 12). Lack of activity of LB on SM cariogenicity persisted even when 10⁵ times higher concentration of the probiotic was tested. Coaggregation was not observed. In conclusion, findings suggest that LB does not reduce cariogenicity of SM in a validated experimental caries model.

Genetic influences on dental enamel that impact caries differ between the primary and permanent dentitions.

Clinically, primary and permanent teeth are distinct anatomically and the presentation of caries lesions differs between the two dentitions. Hence, the possibility exists that genetic contributions to tooth formation of the two dentitions are different. The purpose of this study was to test the hypothesis that genetic associations with an artificial caries model will not be the same between primary and permanent dentitions. Enamel samples from primary and permanent teeth were tested for microhardness at baseline, after carious lesion creation, and after fluoride application to verify association with genetic variants of selected genes. Associations were found between genetic variants of ameloblastin, amelogenin, enamelin, tuftelin, tuftelin interactive protein 11, and matrix metallopeptidase 20 and enamel from permanent teeth but not with enamel from primary teeth. In conclusion, our data continue to support that genetic variation may impact enamel development and consequently individual caries susceptibility. These effects may be distinct between primary and permanent dentitions.

Antimicrobial Capacity of Casein Phosphopeptide/Amorphous Calcium Phosphate and Enzymes in Glass Ionomer Cement in Dentin Carious Lesions.

To evaluate the ability of casein phosphopeptide/amorphous calcium phosphate (CPP/ACP) and lysozyme, lactoferrin, and lactoperoxidase (LLL) added to glass ionomer cement (GIC) to inhibit the growth of S. mutans in a caries model. Eighty permanent third molars were selected. The dentin of these teeth was exposed and flattened. Except for the coronal dentin, the specimens were waterproofed, autoclaved, and submitted to cariogenic challenge with standard strain of S. mutans. The carious lesions were sealed as follows: group 1 (n=20): GIC without additives; group 2 (n=20): GIC + CPP/ACP; group 3 (n=20): GIC + LLL; group 4 (n=20): GIC + CPP/ACP + LLL. S. mutans counts were performed before the caries were sealed (n=5), after 24 hours (n=5), at 1 month (n=5), and at 6 months (n=5). The results were analyzed using descriptive statistical analysis and the Kruskal-Wallis test (Student-Newman-Keuls test). GIC + LLL caused a significant reduction of S. mutans 1 month after sealing (p<0.01); however, there was a significant growth of S. mutans 6 months after sealing. GIC, GIC + CPP/ACP, and GIC + CPP/ACP + LLL showed similar behavior with significant reduction of S. mutans after 24 hours (p<0.05) and increase after 1 and 6 months. The addition of LLL to GIC increases the antimicrobial action of GIC on S. mutans. This leads to control of bacterial biofilm for 1 month, thus stopping the progression of carious lesions.

Penetration of Streptococcus sobrinus and Streptococcus sanguinis into dental enamel

The aim of this pilot study was to assess the difference in virulence of acidogenic and aciduric oral streptococci in an in vitro caries model using their penetration depths into dental enamel.30 caries-free extracted molars from 11- to 16-year-olds were cleaned ultrasonically for 1 min with de-ionized water and, after air-drying, embedded in epoxy resin. After 8-h of setting at room temperature, the specimens were ground on the buccal side with SiC-paper 1200 (particle size 13–16 μm). Enamel was removed in circular areas sized 3 mm in diameter; the mean depth of removed enamel was 230 ± 60 μm. 15 specimens each were incubated anaerobically under standardized conditions with 24 h-cultures of Streptococcus sanguinis 9S or Streptococcus sobrinus OMZ 176 in Balmelli broth at 37 ± 2 °C; the pH-values of the broths were measured at the beginning and end of each incubation cycle. After 2, 4, 6, 8, and 10 weeks 3 teeth each were fixed in 2.5% glutaraldehyde in cacodylate buffer for 24 h, washed 3× and dehydrated 30–60min by sequential washes through a series of 30–100% graded ethanol.The teeth were cut in half longitudinally; afterward, two slits were made to obtain fracture surfaces in the infected area. After critical-point-drying the fragments were gold-sputtered and viewed in a scanning electron microscope at magnifications of ×20-20,000. After 10 weeks of incubation, penetration of S. sanguinis of 11.13 ± 24.04 μm below the break edges into the enamel was observed. The invasion of S. sobrinus reached depths of 87.53 ± 76.34 μm. The difference was statistically significant (paired t test: p = 0.033). The experimental penetration depths emphasize the importance of S. sanguinis versus S. sobrinus in the context of the extended ecological plaque hypothesis.

Genetic factors affecting dental caries risk.

This article reviews the literature on genetic aspects of dental caries and provides a framework for the rapidly changing disease model of caries. The scope is genetic aspects of various dental factors affecting dental caries. The PubMed database was searched for articles with keywords 'caries', 'genetics', 'taste', 'diet' and 'twins'. This was followed by extensive handsearching using reference lists from relevant articles. The post-genomic era will present many opportunities for improvement in oral health care but will also present a multitude of challenges. We can conclude from the literature that genes have a role to play in dental caries; however, both environmental and genetic factors have been implicated in the aetiology of caries. Additional studies will have to be conducted to replicate the findings in a different population. Identification of genetic risk factors will help screen and identify susceptible patients to better understand the contribution of genes in caries aetiopathogenesis. Information derived from these diverse studies will provide new tools to target individuals and/or populations for a more efficient and effective implementation of newer preventive measures and diagnostic and novel therapeutic approaches in the management of this disease.

Income-based life-course models of caries in 30-year-old Australian adults.

To assess income-based life-course models between the age of 13 and 30 years and caries in young adults. In 1988-89, n = 7673 South Australian school children aged 13 years were sampled with n = 4604 children (60.0%) and n = 4476 parents (58.3%) returning questionnaires. In 2005-06, n = 632 baseline study participants aged 30 years responded (43.0% of those traced and living in Adelaide). Life-course models representing critical period, cumulative risk and social mobility were constructed using income tertiles at ages 13 and 30 years. Critical period was evaluated by comparing the low tertile with the middle and higher tertiles at age 13. Cumulative risk was evaluated by coding the low tertile as 2, the middle tertile as 1 and highest tertile as 0, and summing to produce a cumulative risk score categorized into lower (score 0-1), moderate (score of 2) and higher risk (scores 3-4). Social mobility was classified using tertiles into stable disadvantaged, downwardly mobile, stable middle income, upwardly mobile and stable advantaged. Models adjusting for sex, visiting and toothbrushing at age 30 showed no association between caries at age 30 and low income at age 13 years (critical period model). Compared to the low cumulative risk group based on income, decayed teeth (RR = 1.6) and missing teeth (RR = 7.2) were higher (P < 0.05) in the higher risk group, and missing teeth (RR = 6.0) were higher in the moderate risk group (cumulative risk model). There were more (P < 0.05) decayed teeth in the disadvantaged (RR = 3.1) and stable middle income groups (RR = 2.2), more missing teeth for those classified as disadvantaged (RR = 6.4), stable middle (RR = 6.3) and downwardly mobile (RR = 2.8), and higher DMFT for the disadvantaged group (RR = 1.5) compared to the upwardly mobile group (social mobility model). Socioeconomic advantage and upward mobility were associated with fewer decayed and missing teeth at age 30 years. Life-course models of cumulative risk and social mobility influenced oral health outcomes across childhood to adulthood.

A hypothetical role for vitamin K2 in the endocrine and exocrine aspects of dental caries

The growing interest in oral/systemic links demand new paradigms to understand disease processes. New opportunities for dental research, particularly in the fields of neuroscience and endocrinology will emerge. The role of the hypothalamus portion of the brain cannot be underestimated. Under the influence of nutrition, it plays a significant role in the systemic model of dental caries. Currently, the traditional theory of dental caries considers only the oral environment and does not recognize any significant role for the brain. The healthy tooth, however, has a centrifugal fluid flow to nourish and cleanse it. This is moderated by the hypothalamus/parotid axis which signals the endocrine portion of the parotid glands. High sugar intake creates an increase in reactive oxygen species and oxidative stress in the hypothalamus. When this signaling mechanism halts or reverses the dentinal fluid flow, it renders the tooth vulnerable to oral bacteria, which can now attach to the tooth’s surface. Acid produced by oral bacteria such as Strep Mutans and lactobacillus can now de-mineralize the enamel and irritate the dentin. The acid attack stimulates an inflammatory response which results in dentin breakdown from the body’s own matrix metalloproteinases. Vitamin K2 (K2) has been shown to have an antioxidant potential in the brain and may prove to be a potent way to preserve the endocrine controlled centrifugal dentinal fluid flow. Stress, including oxidative stress, magnifies the body’s inflammatory response. Sugar can not only increase oral bacterial acid production but it can concurrently reduce the tooth’s defenses through endocrine signaling. Saliva production is the exocrine function of the salivary glands. The buffering capacity of saliva is critical to neutralizing the oral environment. This minimizes the de-mineralization of enamel and enhances its re-mineralization. K2, such as that found in fermented cheese, improves salivary buffering through its influence on calcium and inorganic phosphates secreted. Data collected from several selected primitive cultures on the cusp of civilization demonstrated the difference in dental health due to diet. The primitive diet group had few carious lesions compared to the group which consumed a civilized diet high in sugar and refined carbohydrates. The primitives were able to include the fat soluble vitamins, specifically K2, in their diet. More endocrine and neuroscience research is necessary to better understand how nutrition influences the tooth’s defenses through the hypothalamus/parotid axis. It will also link dental caries to other inflammation related degenerative diseases such as diabetes.

Biomimetic remineralization of demineralized dentine using scaffold of CMC/ACP nanocomplexes in an in vitro tooth model of deep caries.

Currently, it is still a tough task for dentists to remineralize dentine in deep caries. The aim of this study was to remineralize demineralized dentine in a tooth model of deep caries using nanocomplexes of carboxymethyl chitosan/amorphous calcium phosphate (CMC/ACP) based on mimicking the stabilizing effect of dentine matrix protein 1 (DMP1) on ACP in the biomineralization of dentine. The experimental results indicate that CMC can stabilize ACP to form nanocomplexes of CMC/ACP, which is able to be processed into scaffolds by lyophilization. In the single-layer collagen model, ACP nanoparticles are released from scaffolds of CMC/ACP nanocomplexes dissolved and then infiltrate into collagen fibrils via the gap zones (40 nm) to accomplish intrafibrillar mineralization of collagen. With this method, the completely demineralized dentine was partially remineralized in the tooth mode. This is a bottom-up remineralizing strategy based on non-classical crystallization theory. Since nanocomplexes of CMC/ACP show a promising effect of remineralization on demineralized dentine via biomimetic strategy, thereby preserving dentinal tissue to the maximum extent possible, it would be a potential indirect pulp capping (IPC) material for the management of deep caries during vital pulp therapy based on the concept of minimally invasive dentistry (MID).

Dental caries and social factors: impact on quality of life in Brazilian children

The objective of this study was to evaluate the impact of dental caries and social determinants in the Oral Health Related Quality of Life (OHRQoL) of children in Belo Horizonte, Brazil. This is a population-based cross-sectional study with a representative sample of 1,204 children aged 8 to 10 years randomly selected from 19 public and private schools. The children were clinically examined at school by two trained and calibrated examiners (Kappa = 0.78 - 1.00). The Decayed, Missing and Filled Teeth Index (DMF-T and dmf-t) was used for the diagnosis of dental caries. The social factors were determined by parents'/caregivers' schooling, household income, number of people in the household, type of school, and by the Social Vulnerability Index. The Brazilian version of the Child Perceptions Questionnaire for ages 8 to 10 years was used to assess the impact on quality of life. A total of 278 (23.1%) out of 1,204 children had at least one cavitated carious lesion and 47.0% presented a negative impact on OHRQoL. In the final multivariate Poisson's regression model, household income and presence of untreated dental caries were statistically associated with a negative impact on OHRQoL (p < 0.001).Children with dental caries and from low-income families had a higher negative impact on OHRQoL.

Effect of epigallocatechin-3-gallate application for remaining carious dentin disinfection.

Context:Epigallocatechin-3-gallate (EGCG) is a flavonoid extracted from green tea that demonstrated antimicrobial activity.Aims:To evaluate the efficacy of EGCG 0.5%, 1%, and 2% concentrations as an antimicrobial solution in dentin caries-like lesions induced in a bacterial-based in vitro model.Materials and Methods:Twenty-five human dentin specimens were submitted to a microbial-based caries model by immersion in brain heart infusion (BHI) broth inoculated with Streptococcus mutans UA159, for 5 days. After the demineralization period, the specimens were randomly divided into groups: Group I: 0.9% saline solution; Group II: 2% chlorhexidine digluconate; Group III: 0.5% EGCG; Group IV: 1% EGCG; and Group V: 2% EGCG. After the treatments, carious dentin samples were harvested from dentin specimens and analyzed by colony-forming unit (CFU) counts. Data were analyzed by ANOVA and Tukey's test.Results:Log reduction values (SD, CFU.mg-1) for Groups I–V were: 5.02 (0.16), 3.96 (0.43), 4.74 (0.26), 4.89 (0.56), and 4.91 (0.40), respectively. There was no statistical difference between the EGCG concentrations and saline solution (P > 0.05). Furthermore, there was no statistical difference between EGCG concentrations (P > 0.05). However, there was a statistically significant difference between the chlorhexidine digluconate group and the other groups (P < 0.05).Conclusion:EGCG at the studied concentrations were not effective in eliminating S. mutans from dentin caries-like lesions.

Early childhood caries and intake of 100 percent fruit juice: Data from NHANES, 1999-2004

The results of several studies conducted in the United States show no association between intake of 100 percent fruit juice and early childhood caries (ECC). The authors examined this association according to poverty and race/ethnicity among U.S. preschool children. The authors analyzed data from the 1999-2004 National Health and Nutrition Examination Survey (NHANES) for 2,290 children aged 2 through 5 years. They used logistic models for caries (yes or no) to assess the association between caries and intake of 100 percent fruit juice, defined as consumption (yes or no), ounces (categories) consumed in the previous 24 hours or usual intake (by means of a statistical method from the National Cancer Institute). The association between caries and consumption of 100 percent fruit juice (yes or no) was not statistically significant in an unadjusted logistic model (odds ratio [OR], 0.76; 95 percent confidence interval [CI], 0.57-1.01), and it remained nonsignificant after covariate adjustment (OR, 0.89; 95 percent CI, 0.63-1.24). Similarly, models in which we evaluated categorical consumption of 100 percent juice (that is, 0 oz; > 0 and ≤ 6 oz; and > 6 oz), unadjusted and adjusted by covariates, did not indicate an association with ECC. Our study findings are consistent with those of other studies that show consumption of 100 percent fruit juice is not associated with ECC.

On the initial propagation of dental caries.

A multi-dimensional model for dental caries is applied to study the shape of caries lesions in a realistic tooth geometry and to examine the rate of progress of caries. An upgraded model, taking into account the outer prismless enamel layer, is derived and solved. The model demonstrates the importance of this layer in delaying the onset of caries. The conclusions are discussed in light of experimental results.

Simple predictive model for early childhood caries of chilean children

ABSTRACT Introduction: Early Childhood Caries (ECC), in both industrialized and developing countries, is the most prevalent chronic disease in childhood and it is still a health public problem, affecting mainly populations considered as vulnerable, despite being preventable. Objective The purpose of this study was to obtain a simple predictive model based on risk factors for improving public health strategies for ECC prevention for 3-5 year-old children. Methods - Clinical, environmental and psycho-socio-cultural data of children (n=250) aged 3-5 years, of both genders, from the Health Centers, were recorded in a Clinical History and Behavioral Survey. Results-24% of children presented behavioral problems (bizarre behavior was the main feature observed as behavioral problems). The variables associated to dmf ?4 were: bad children temperament (OR=2.43 [1.34, 4.40]) and home stress (OR=3.14 [1.54, 6.41]). It was observed that the model for male gender has higher accuracy for ECC (AUC= 78%, p-value=0.000) than others. Conclusions- Based on the results, we proposed a model where oral hygiene, sugar intake, male gender, and difficult temperament are main factors for predicting ECC. This model could be a promising tool for cost-effective early childhood caries control. RESUMEN Introducción: Las caries temprana de la infancia (CTI), a pesar de ser una enfermedad prevenible, permanece como uno de los problemas de salud pública, tanto en países industrializados como en los que están en vías de desarrollo, afectando principalmente a poblaciones vulnerables. Objetivo: el objetivo de este trabajo fue generar un modelo sencillo basado en factores de riesgo que sea predictivo del riesgo de CTI en niños de 3-5 años de edad a fin de mejorar las estrategias preventivas a nivel de salud pública. Métodos: Se recolectaron datos clínicos, del hogar y psico-socio-cultural de niños (n=250) de ambos sexos que concurren a centros de salud en la región del Bio Bio –Chile mediante historia clínica y encuesta de comportamiento. Resultados: 24% de los niños presentó problemas de comportamiento (un comportamiento extraño fue la principal característica observada como problema de comportamiento). Las variables asociadas a ceo ?4 fueron: mal temperamento del niño (OR=2,43 [1,34; 4,40]) y estrés del hogar (OR=3,14 [1,54; 6,41]). Se observe que el modelo estratificado por género masculino fue el que presentó la mayor precisión diagnóstica de CTI (AUC= 78%, p-valor=0.000); además Conclusiones: Proponemos un modelo donde la higiene oral, el consumo de azúcar, el género masculino y el mal temperamento son los principales factores de predictivos de CTI. Este modelo podría ser una herramienta promisoria para el costo-efectividad del control de caries temprana.

Enamel Carious Lesion Development in Response to Sucrose and Fluoride Concentrations and to Time of Biofilm Formation: An Artificial-Mouth Study.

The aim of this study was to evaluate both sucrose and fluoride concentrations and time of biofilm formation on enamel carious lesions induced by an in vitro artificial-mouth caries model. For Study 1, biofilms formed by streptococci and lactobacilli were grown on the surface of human enamel slabs and exposed to artificial saliva containing 0.50 or 0.75 ppmF (22.5 h/d) and broth containing 3 or 5% sucrose (30 min; 3x/d) over 5 d. In Study 2, biofilms were grown in the presence of 0.75 ppmF and 3% sucrose over 3 and 9 days. Counts of viable cells on biofilms, lesion depth (LD), and the integrated mineral loss (IML) on enamel specimens were assessed at the end of the tested conditions. Counts of total viable cells and L. casei were affected by sucrose and fluoride concentrations as well as by time of biofilm formation. Enamel carious lesions were shallower and IML was lower in the presence of 0.75 ppmF than in the presence of 0.50 ppmF (P < 0.005). No significant effect of sucrose concentrations was found with respect to LD and IML (P > 0.25). Additionally, deeper lesions and higher IML were found after 9 d of biofilm formation (P < 0.005). Distinct sucrose concentrations did not affect enamel carious lesion development. The severity of enamel demineralization was reduced by the presence of the higher fluoride concentration. Additionally, an increase in the time of biofilm formation produced greater demineralization. Our results also suggest that the present model is suitable for studying aspects related to caries lesion development.

Influence of Pastes Containing Casein Phosphopeptide-amorphous Calcium Phosphate on Surface of Demineralized Enamel

The purpose of the study was to evaluate the surface characteristics of demineralized enamel after treatment with pastes containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) or casein phosphopeptide-amorphous calcium fluoride phosphate (CPP-ACFP) and to compare their efficacy with that of 0.05% NaF. Following formation of the artificial carious lesion, enamel slabs were divided into 4 groups (CPP-ACP, CPP-ACFP, 0.05% NaF and control) and submitted to a chemical caries model. Remineralization potential was examined using scanning electron microscope, energy-dispersive spectroscopy (EDS) and microhardness test. Scanning electron microphotographs were analyzed for area, minimal, maximal and mean diameter, perimeter, roundness and number of enamel defects and percentage of tooth surface affected by defects. Treatment with 0.05% NaF partly reduced the appearance of enamel defects when compared with irregular demineralized enamel. Treatment with CPP-ACP or CPP-ACFP resulted in occlusion of defects which produced more flattened enamel surface. Image analysis revealed reduction of the dimensions of the defects in the 3 experimental groups. Treatment with CPP-ACFP decreased the number of enamel defects when compared with demineralized enamel. The EDS analysis did not show differences in Ca/O, P/O and Ca/P ratios between the groups (P>0.05). Microhardness test revealed significant effects of CPP-ACP and CPP-ACFP (P<0.05). Pastes containing CPP-ACP or CPP-ACFP showed potential to remineralize enamel surface lesions.

Anticaries effect of an antioxidant-rich apple concentrate on enamel in an experimental biofilm-demineralization model

To assess the anticaries activity of an antioxidant-rich apple concentrate (ARAC) in an experimental biofilm caries model on enamel. A validated caries model with Streptococcus mutans UA159 biofilms was used. Biofilms were formed on enamel slabs during 5 days. To mimic cariogenic challenges, triplicate slabs were exposed three times per day for 5 min to 10% sucrose followed by five additional minutes of exposure to serial dilutions of ARAC in 0·9% NaCl. A triplicate slab exposed to 10% sucrose followed by 0·9% NaCl served as caries-positive control. Acidogenicity was estimated by medium pH twice per day. After the experimental phase, biofilms were recovered to determine biomass, viable bacteria and intra- and extracellular polysaccharides. Slabs were used to estimate demineralization by the percentage of surface microhardness loss (%SHL). Differences among treatments were analysed by anova and Bonferroni test (P < 0·05). Streptococcus mutans biofilms were exposed to ARAC after a cariogenic challenge with sucrose-induced lower enamel demineralization than the positive control. The highest dilution of ARAC at 1 : 100 000 (v/v) showed the most marked reduction in demineralization of about 57%. Although no differences were observed in the number of bacterial cells, the intracellular polysaccharides or in the biomass (P > 0·05), the highest dilution of the apple concentrate induced significantly lower extracellular polysaccharide formation by the biofilm. An apple concentrate in low concentrations appears to have a potential anticaries activity on enamel. Data suggest a metabolic rather than an antimicrobial mechanism, but further research is needed. Phenolic compounds contained in apple concentrates seem to have anticaries properties that may be effective even in the presence of sucrose and in very low doses. Nutritional interventions that do not require rescinding from sucrose might be derived from these findings.

The preventive effect of grape seed extract on artificial enamel caries progression in a microbial biofilm-induced caries model

ObjectivesThe aim of this study was to evaluate the effect of grape seed extract (GSE) on enamel caries lesion formation in an in vitro Streptococcus mutans biofilm model. MethodsEnamel fragments were prepared from bovine incisors and divided into six treatment groups (n=12): inoculated Brain Heart Infusion with 1% sucrose (BHIS), 1mg/mL GSE, 2mg/mL GSE, 3mg/mL GSE, 10ppm fluoride as NaF, and uninoculated BHIS. For biofilm formation, tooth fragments were incubated anaerobically in polystyrene 6-well tissue culture plates containing BHIS, the respective agents, and S. mutans (1×105CFU/mL) for 24h at 37°C. Culture medium was replaced with fresh BHIS and respective agents daily over a 7-day period. Following caries lesion formation, lesion depth (LD) and relative optical density (ROD) were determined by polarized light microscopy (PLM) and confocal laser scanning microscopy (CLSM), respectively, to evaluate lesion progression. ResultsLDs of the 2mg/mL GSE group (122.86±13.41μm) and the 3mg/mL GSE group (111.92±11.39μm) were significantly smaller than those of the 1mg/mL GSE (198.33±17.70μm) and control groups (210.86±15.50μm) (p<0.05). Compared with the 2mg/mL and 3mg/mL groups, the control and 1mg/mL GSE groups showed significantly lower ROD values when depth was less than 200μm, indicating greater mineral loss. ConclusionsDose-dependent GSE inhibits in vitro enamel caries formation due to its ability to suppress growth of S. mutans and the formation of biofilm. Clinical significanceGrape seed extract may be a novel virulence-targeted natural antimicrobial agent for caries prevention.

Fatty acid effect on sucrose-induced enamel demineralization and cariogenicity of an experimental biofilm-caries model.

Based on scarce evidence, fatty acids have been described as anticariogenic. The aim was to evaluate the effect of different types of fatty acids on enamel demineralization and on the cariogenic properties of Streptococcus mutans biofilms on a biofilm/caries model. Mature biofilms of S. mutans UA159 growing on bovine enamel slabs were exposed to 10% sucrose for 5 min, 3 times per day followed by exposure to a panel of free fatty acids, including monounsaturated (oleic), polyunsaturated (linoleic) and saturated (stearic) fatty acids, in concentrations of 0.1, 1 and 10 mM for five additional minutes. Enamel demineralization was determined before and after the experiments by microhardness. Slabs were retrieved to analyze biofilm biomass, viable bacterial counts and polysaccharide production. Biofilms exposed to sucrose, followed by oleic and linoleic acids, showed less demineralization than sucrose alone (p < 0.05). Biomass, S. mutans colonies and insoluble extracellular polysaccharide production were reduced from the biofilms treated with oleic and linoleic fatty acids (p < 0.05). No differences with the positive control were observed with the saturated stearic acid. Poly and monounsaturated fatty acids presented to S. mutans biofilms after a cariogenic challenge appear to reduce demineralization on enamel and to interfere with cariogenicity of S. mutans biofilms.